I’m glad you find the plugin useful; thanks. I want to make sure I understand your questions. Let me break the questions down and see if I’m on the right track. In your first question:
- You say ‘when i try “set a post thumbnail”‘; do you mean the “Set Featured Image” link in the Featured Image metabox on the Edit Post screen, or the “Set Featured Image” tab on the left side of the Media Manager “media upload window” (I don’t see anything specifically labeled “set a post thumbnail”)?
- You say ‘change filter with mla categories‘. Do you mean the dropdown list that starts with “All Att. Categories” when you open the upload window? It sounds like you are pulling down the list and selecting a specific Att. Category value to filter the list; is that right?
- You say ‘When i use media upload on another field it works‘. What do you mean by ‘another field‘?
If I have understood your question, you are trying to filter your Media Library by selecting a specific value in the Att. Category taxonomy and there are no attachments showing up in the media upload window. I have not been able to reproduce this problem on my test system, but here are two additional questions that might help us find the problem.
First, have you tried the “Insert Media” and “Create Gallery” tabs at the left of the media upload window? Do those features display some attachments when you filter by Att. Category?
Second, does the value you are selecting on show up in the Att. Category column on the Media/Assistant submenu table?
Please look over the above questions and let me know if I am understanding your question. If I have more information I can be more helpful.
For your second question, it sounds like you are using other plugins that enhance the media upload window, and those other plugins do not include the MLA enhancements on the media upload window toolbar. If that’s right, I regret that the news is not good. Here are two earlier support topics with similar questions:
filter not showing in modal popup window for image widget
Problem with Simplefields
The media upload window is a new addition to WordPress and the techniques for enhancing it with plugins are not very clear.